The aim of this study was to evaluate the effects of miR-26a on Beclin 1 expression in retinoblastoma (RB) cell lines (Y79 and WERi-RB-1). RB cells were transfected with miR-26a mimic, antagomir-26a, or control mimic. The Beclin 1 mRNA and protein levels were detected by quantitative polymerase chain reaction and western blot, respectively. The activity of Beclin 1 3ꞌ-UTR reporter gene was detected with the luciferase assay. After transfection with miR-26a mimic, Beclin 1 mRNA and protein levels as well as the activity of the 3'-UTR reporter gene decreased.